Difference between revisions of "Dreyer Table Mark III"

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(Created page with 'The '''Mark III Dreyer Table''' was a refined version of the Original Dreyer Table and was the first Dreyer Fire Control Table provided for naval service. [[Mark III Drey…')
 
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The '''Mark III Dreyer Table''' was a refined version of the [[Original Dreyer Table]] and was the first [[Dreyer Fire Control Table]] provided for naval service. [[Mark III Dreyer Table|Mark III table]], and probably first deployed in 1915.<ref name=Brooks176>Brooks. ''Dreadnought Gunnery and the Battle of Jutland''.  p. 176.</ref>  With a footprint 23% smaller than the Mark III table's,<ref>''Handbook of Captain F.C. Dreyer's Fire Control Tables, 1918''.  p. 90.</ref> it could more comfortably fit within the smaller [[Transmitting Station|transmitting stations]] of the early [[Dreadnought|dreadnought]] [[Battleship|battleships]] and [[Battlecruiser|battlecruisers]] into which it was retro-fitted.
+
[[File:DreyerTableMarkIII_drawing_c1912.jpg|thumb|512px|'''Mark III Dreyer Table c1912'''<br>Table now has a single deflection drum but lacks the second deflection drum added around February 1913. ]]
 +
The '''Mark III Dreyer Table''' was a refined version of the [[Original Dreyer Table]] and was the first [[Dreyer Fire Control Table]] provided for naval service, first deployed in 1912 in ''Monarch''.<ref>Brooks. ''Dreadnought Gunnery and the Battle of Jutland''.  p. 159.</ref>
  
 +
[[File:RenderDreyerMarkIII1918Front.jpg|thumb|360px|'''Mark III Dreyer Table c1918, front'''<br>This illustrates the [[Standard Bearing Plot]] and its [[Deflection Totaliser]] which were featured so prominently in the 1918 Handbook, but which may never have been widely deployed if at all.]]
  
−
[[File:DreyerTableMarkI_front.jpg|thumb|512px|'''Mark I Dreyer Table as it appeared by 1918, front''' ]]
+
==Development==
 +
[[File:DreyerTableMarkIII_schematic_c1912.jpg|thumb|360px|'''Mark III Dreyer Table Schematic c1912'''<br>Table seems to lack any deflection drum at all, which was one of its primary improvements from the Original Table. ]]
 +
[[File:DreyerTableMarkIII_elevationAndPlan_Mar1912.jpg|thumb|360px|'''Mark III Dreyer Table design drawing from March, 1912.'''<br>This early drawing focuses only on the general layout, but it is clear from the overall context that the early thinking was correct to the extent that it was never revisited, and the headboard is even in place, illustrating the early focus on helm-free design from the gyro-compass and relay that are already outlined there.  The early bearing plot runs the depth of the table, and the bearing clock is also clearly indicated by the handle on the dumaresq. ]]
 +
[[File:DreyerTableMarkIII_elevationAndPlan_June1912.jpg|thumb|360px|'''Mark III Dreyer Table design drawing from June, 1912'''<br>This drawing illustrates detailed thinking on positioning the components on the table and integrating their function as required.  The design of the dumaresq and its underslung bearing clock may have been completed, as its handle is now angled as it would remain in subsequent drawings. ]]
  
−
[[File:DreyerTableMarkI_back.jpg|thumb|512px|'''Mark I Dreyer Table as it appeared by 1918, back''' ]]
+
[[File:RenderDreyerMarkIII1918Back.jpg|thumb|360px|'''Mark III Dreyer Table as could have appeared c1918, back'''<br>Another view of the same configuration rendered above shows a [[Wind Dumaresq]] on the right would have occupied the area freed up by use of the smaller bearing plot.]]
  
−
[[File:DreyerTableMarkI_diagram.jpg|thumb|512px|'''Mark I Dreyer Table c1918, schematic''']]
+
[[File:DreyerTableMarkIII_operators_1918.jpg|thumb|360px|'''Mark III Dreyer Table operators, c1918'''<br>This is also based on the configuration outlined in the 1918 Handbook but perhaps not really adopted in service. ]]
  
−
[[File:DreyerTableMarkIAndIStar_operators.jpg|thumb|512px|'''Mark I Dreyer Table as it would have been crewed in 1918''' ]]
 
−
 
−
==Development==
 
 
Five of what was to become known by March 1914 as the Mark III tables were ordered in February 1912 even as the design was being finalised.  It generally resembled the capabilities of the original Dreyer table, but by March 1912, it boasted these improvements:
 
Five of what was to become known by March 1914 as the Mark III tables were ordered in February 1912 even as the design was being finalised.  It generally resembled the capabilities of the original Dreyer table, but by March 1912, it boasted these improvements:
 
* the paper plots were now driven by electric motors (with a fallback to hand crank)
 
* the paper plots were now driven by electric motors (with a fallback to hand crank)
Line 18: Line 20:
 
* a cylindrical deflection drum was added to the bearing plot to relate bearing rate to [[Dumaresq Deflection]].
 
* a cylindrical deflection drum was added to the bearing plot to relate bearing rate to [[Dumaresq Deflection]].
  
−
By February 1913, the design had further matured:(TH page 47-48)
+
By February 1913, the design had further matured to "probably include" the following:<ref>Dreyer & Usborne. ''Technical History'', pp.47-8.</ref>
−
* A [[Bearing Clock|bearing clock]] was added to help keep dumaresq updated for enemy bearing.
+
* A [[Bearing Clock|bearing clock]] was added to help keep dumaresq updated for enemy bearing.<ref>this is somewhat ambiguously stated</ref>
 
* A second deflection drum was to be added to the bearing plot to relate bearing rate to [[Gun Deflection]].
 
* A second deflection drum was to be added to the bearing plot to relate bearing rate to [[Gun Deflection]].
 
* Automatic transmission of ranges to the guns.  The design drawing for what would later be called  
 
* Automatic transmission of ranges to the guns.  The design drawing for what would later be called  
 
* The differential gear (later known as the [[Spotting Corrector|''spotting corrector'']]) considered optional in previous drawings was to be issued with all further tables.
 
* The differential gear (later known as the [[Spotting Corrector|''spotting corrector'']]) considered optional in previous drawings was to be issued with all further tables.
−
* A means of factoring in own ship's lateral [[Slip|''slip'']] through the water as it turns (it is not clear that this ever materialised &mdash; it was handled inelegantly even in postwar use of late model Dreyer tables{{CN}}).
+
* A means of transferring rates from dumaresq to range clock.<ref>This was not to materialise until the advent of the [[Electrical Dumaresq]]</ref>
 +
* A means of factoring in own ship's lateral [[Slip|''slip'']] through the water as it turns, but this did not work out readily and was deferred in July 1914, and allowed to fall into obscurity.<ref>Brooks.  p. 169.</ref>Slip was handled inelegantly even in postwar use of late model Dreyer tables.{{CN}}
 
* Plans to relay enemy heading and range rate to the control position (possibly this was considerably delayed, later to be manifested as [[''The Repeater'']] outlined in the 1918 Handbook.
 
* Plans to relay enemy heading and range rate to the control position (possibly this was considerably delayed, later to be manifested as [[''The Repeater'']] outlined in the 1918 Handbook.
−
* A [[Time-of-Flight]] corrector for gun range was mentioned, but a lack of further mention of it suggests that this was handled by the separate [[Dreyer Calculator]] throughout the war.
+
* A [[Time-of-Flight]] corrector for gun range was mentioned, but this correction continued to be calculated by the separate [[Dreyer Calculator]] and entered via the spotting corrector differential throughout the war and into the 1930s.<ref>Brooks.  p. 169, footnote 141.</ref>
−
* Vague allusion to plans to permit the plotting of cuts from multiple rangefinders
+
* Equipment to permit the plotting of ranges from multiple rangefinders.  This did not happen promptly.  See the discussion on the general evolution of [[Dreyer Fire Control Table#Range Plot|Dreyer range plots]].
  
 
{| border="1" cellpadding="5" cellspacing="0"  
 
{| border="1" cellpadding="5" cellspacing="0"  
 
|-
 
|-
−
| bgcolor=CEDFF2 colspan="2"|'''Overall Dimensions (1918)'''<ref>Dreyer Handbook p. 90.</ref>
+
| bgcolor=CEDFF2 colspan="2"|'''Overall Dimensions (1918)'''<ref>Dreyer Handbook, 1918 p. 90.</ref>
 
|-valign="top"
 
|-valign="top"
 
| Width  
 
| Width  
Line 51: Line 54:
  
 
===Dumaresq===
 
===Dumaresq===
−
An adapted [[Dumaresq Mark VI*]] with fixed and simplified dial plate was fitted, with a means of permitting the gyro-compass to maintain own heading.   
+
An adapted [[Dumaresq Mark VI]] with fixed and simplified dial plate was fitted, with a means of permitting the gyro-compass to maintain own heading.  A bearing clock and range clock were housed underneath it.
  
 
===Range Clock===
 
===Range Clock===
Line 59: Line 62:
  
 
===Bearing Clock===
 
===Bearing Clock===
−
A bearing clock was probably also underneath the dumaresq for every Mark III table delivered.  Despite its fairly late appearance in design specifications, the handle for setting a bearing rate is clearly visible in drawings dating back to June 1912. (TH Fig. 7.)
+
A bearing clock with a disc-and-roller variable speed drive similar to that of the range clock also sat under the dumaresq.  Despite its fairly late appearance in design specifications, the handle for setting a bearing rate is clearly visible in drawings dating back to June 1912<ref>Technical History, Fig. 7.</ref> and is perhaps illustrated in drawings dating from March 1912.<ref>Technical History, Fig. 4.</ref>
  
−
The clock could be set to any rate between +/- 15 degrees per minute by a handle with an indicator scale jutting out from the base of the dumaresq housing (TH Fig 3 & 7).
+
The clock could be set to any rate between +/- 15 degrees per minute by a handle with an indicator scale jutting out from the base of the dumaresq housing.<ref>Technical History, Figs. 3, 7.</ref>
  
 
===Spotting Corrector===
 
===Spotting Corrector===
 +
{{TBC}} this largely is correct for Mark I table but not Mark III
 +
 
The spotting corrector in the 1918 handbook features:
 
The spotting corrector in the 1918 handbook features:
 
* Output worm shaft for the plot range pencil holder
 
* Output worm shaft for the plot range pencil holder
 
* Spotting handle to enter corrections
 
* Spotting handle to enter corrections
 
* Straddle correction hand (for applying corrections from a [[Dreyer Calculator]])
 
* Straddle correction hand (for applying corrections from a [[Dreyer Calculator]])
−
* [[Gun Range Counter|Gun range counter]] (on the table)
+
* A digital [[Gun Range Counter|Gun range counter]] (on the table)
 
* Commutator to relay gun range to control positions and conning tower
 
* Commutator to relay gun range to control positions and conning tower
 
* A flexible shaft to carry gun range to the deflection drums of the [[Standard Bearing Plot|standard bearing plot]]
 
* A flexible shaft to carry gun range to the deflection drums of the [[Standard Bearing Plot|standard bearing plot]]
−
but lacked a flexible shaft to convey the gun range to a [[Range Master Transmitter]] on the bulkhead.<ref>''Handbook of Captain F.C. Dreyer's Fire Control Tables, 1918''.  p. 15.</ref>  Presumably, this transcription was done by reading aloud the ranges on the gun range counter.
 
  
 
A hand-worked [[Pedalling Clutch|pedalling clutch]] located near the tuning handle allowed the plotted range to be tuned without altering the gun range.
 
A hand-worked [[Pedalling Clutch|pedalling clutch]] located near the tuning handle allowed the plotted range to be tuned without altering the gun range.
  
 
===Range Plot===
 
===Range Plot===
−
The Mark III's range plot set the pattern for those on the later Mark IV, IV* and V tables, a large surface placed on the right, with a [[Range Rate Grid|range rate grid]] positioned over it.   
+
The Mark III's range plot set the pattern for those on the later tables Mark IV, IV*, V and probably II; a large surface placed on the right, with a [[Range Rate Grid|range rate grid]] positioned over it.   
  
 
'''Rate Grid'''
 
'''Rate Grid'''
Line 86: Line 90:
 
* Ambitions for replacing this with a means of plotting cuts from multiple RFs were probably alluding to the failed [[Macnamara's Plotter]].
 
* Ambitions for replacing this with a means of plotting cuts from multiple RFs were probably alluding to the failed [[Macnamara's Plotter]].
 
* Manual [[Brownrigg Keyboard]]s were used on many Dreyer tables by Jutland, but it is unclear which Mark III tables might have had this in place of their initial automated plotting mechanism.
 
* Manual [[Brownrigg Keyboard]]s were used on many Dreyer tables by Jutland, but it is unclear which Mark III tables might have had this in place of their initial automated plotting mechanism.
−
* Manual [[Range Typewriter]]s were being urged for widespread deployment by 1918.<ref name=Brooks176/>
+
* Manual [[Range Typewriter]]s were deployed widely in 1917.<ref>Brooks.  ''Dreadnought Gunnery'', p. 173.</ref>
  
 
'''Range Pencils'''
 
'''Range Pencils'''
−
Initial production tables had a single red pencil to plot [[Clock Range]].  As early drawings imply it was first installed, it appears that the tuning handle had no pedalling clutch and so intrinsically altered clock range and gun range when it was used.  This implies that the tuning handle would only be used at the beginning of an encounter.
+
Initial production tables had a single red pencil to plot [[Clock Range|clock range]].  As early drawings imply it was first installed, it appears that the tuning handle had no pedalling clutch and so intrinsically altered clock range and gun range when it was used.  This implies that the tuning handle would only be used at the beginning of an encounter.
−
 
 
−
Usborne 48-9
 
  
 
{| border="1" cellpadding="5" cellspacing="0"
 
{| border="1" cellpadding="5" cellspacing="0"
 
|-valign="top"
 
|-valign="top"
 
| Plotting Ranges  
 
| Plotting Ranges  
−
| 2,000 - 16,400 yards<br>(a +8,000 yard extended scale added later allowed plotting to 24,400 yards) (DH p. 17.)
+
| 2,000 - 16,400 yards<br>(a +8,000 yard extended scale added later allowed plotting to 24,400 yards)<ref>Dreyer Handbook, 1918 p. 17.</ref>
 
|-
 
|-
 
| Paper width
 
| Paper width
Line 108: Line 110:
 
|-
 
|-
 
|}
 
|}
 +
 +
The extended range scales were likely fitted to tables as opportunity around around the time (1915?) such a modification was made to ???? (Brooks){{CN}}.
  
 
===Bearing Plot===
 
===Bearing Plot===
Line 116: Line 120:
 
==Deployment==
 
==Deployment==
  
−
The Dreyer Handbook of 1918 lists some ships with Mark I tables, with those no longer in active service crossed out by hand at some later date, and those lost before promulgation not listed at all.  Those appearing in that document are footnoted below<ref name=DreyerP3>''Handbook of Captain F.C. Dreyer's Fire Control Tables, 1918''.  p. 3.</ref>.
+
The Dreyer Handbook of 1918 lists some ships with Mark III tables, with those no longer in active service crossed out by hand at some later date, and those lost before promulgation not listed at all.  Those appearing in that document are footnoted below<ref name=DreyerP3>''Handbook of Captain F.C. Dreyer's Fire Control Tables, 1918''.  p. 3.</ref>.
−
 
 
−
In February, 1916 Dreyer was awarded £5,000 by the Ordnance Council for his contributions to fire control.  A list was drawn up which indicated the "Ships in which Dreyer's Fire Control is fitted or being fitted."  Those ships listed under the heading "<u>MARK I (Simple Mechanical Table...)</u>" in this document<ref name=OC1916>"With 'Extract from Recommendations of the Admiralty Members of the Ordnance Council at a Meeting 10.2.16 concerning Dreyer's award' in DRYR 2/1."  Brooks.  ''Dreadnought Gunnery at the Battle of Jutland''.  pp. 175-176.</ref> are footnoted below.
 
  
−
{{TBC}}
+
In 1913, Dreyer listed the ships he claimed actually received the first 5 Mark III tables delivered.<ref name=TH11>Dreyer & Usborne.  ''Technical History''.  pp. 11-2.</ref>
−
replace table
 
  
 
{| border="1" cellpadding="5" cellspacing="0"
 
{| border="1" cellpadding="5" cellspacing="0"
 
|-
 
|-
−
| bgcolor=CEDFF2|'''Ship using Mark I table'''
+
| bgcolor=CEDFF2|'''Ship using Mark III table'''
 
| bgcolor=CEDFF2|'''Date equipped'''
 
| bgcolor=CEDFF2|'''Date equipped'''
 
| bgcolor=CEDFF2|'''Notes'''
 
| bgcolor=CEDFF2|'''Notes'''
 
|-valign="top"
 
|-valign="top"
−
| [[H.M.S. Dreadnought (1906)|''Dreadnought'']]<ref name=DreyerP3/><ref name=OC1916/>
+
| [[H.M.S. King George V (1911)|''King George V'']]<ref name=TH11/><ref name=DreyerP3/>
−
| mid 1916, perhaps by May 25<ref>Roberts. ''Anatomy of the Ship: The Battleship Dreadnought''.  p. 31.</ref>
+
| 1913 or earlier through mid 1918 or beyond
−
| installed in fore TS
+
| retained to end of service<ref>not listed as having another, and decommissioned soon after that source's publication</ref>
−
|-
 
−
| [[H.M.S. Colossus (1910)|''Colossus'']]<ref name=DreyerP3/><ref name=OC1916/>
 
−
| N/A
 
−
|
 
−
|-
 
−
| [[H.M.S. Hercules (1910)|''Hercules'']]<ref name=DreyerP3/>
 
−
| Replaced the [[Original Dreyer Table]] used in this ship<ref>''Pollen Aim Corrector System, Part I. Technical History and Technical Comparison with Commander F. C. Dreyer's Fire Control System'', p. 12.</ref>
 
−
|
 
−
|-
 
−
| [[H.M.S. Neptune (1909)|''Neptune'']]<ref name=DreyerP3/><ref name=OC1916/>
 
−
| ???
 
−
|
 
 
|-
 
|-
−
| [[H.M.S. Collingwood (1908)|''Collingwood'']]<ref name=DreyerP3/><ref name=OC1916/>
+
| [[H.M.S. Thunderer (1911)|''Thunderer'']]<ref name=TH11/><ref name=DreyerP3/>
−
| ???
+
| 1913 or earlier through mid 1918 or beyond
−
|  
+
| retained to end of service{{INF}}
 
|-
 
|-
−
| [[H.M.S. St. Vincent (1908)|''St. Vincent'']]<ref name=DreyerP3/><ref name=OC1916/>
+
| [[H.M.S. Monarch (1910)|''Monarch'']]<ref name=TH11/><ref name=DreyerP3/>
−
| ???
+
| 1913 or earlier through mid 1918 or beyond
−
|  
+
| retained to end of service{{INF}}
 
|-
 
|-
−
| [[H.M.S. Vanguard (1909)|''Vanguard'']]<ref name=OC1916/>
+
| [[H.M.S. Lion (1910)|''Lion'']]<ref name=TH11/>
−
| ???
+
| 1913 or earlier through Jutland at least{{CN}}
−
|  
+
| replaced at some point with Mark IV* table
 
|-
 
|-
−
| [[H.M.S. Agincourt (1913)|''Agincourt'']]<ref name=DreyerP3/>
+
| [[H.M.S. Princess Royal (1911)|''Princess Royal'']]<ref name=TH11/>
−
| ???
+
| 1913 or earlier through Jutland at least{{CN}}
−
|  
+
| replaced at some point with Mark IV* table
 
|-
 
|-
−
| [[H.M.S. Erin (1913)|''Erin'']]<ref name=DreyerP3/><ref name=OC1916/>
+
| [[H.M.S. Excellent (Gunnery Training School)|''Excellent'']]<ref name=DreyerP3/>
−
| ???
+
| acquired after Jutland
−
|  
+
| probably taken from ''Lion'' or ''Princess Royal''
 
|-
 
|-
−
| [[H.M.S. Bellerophon (1907)|''Bellerophon'']]<ref name=DreyerP3/><ref name=OC1916/>
+
| [[Chatham Gunnery School]]<ref name=DreyerP3/>
−
| before [[Battle of Jutland|Jutland]]<ref name=Brooks176/>
+
| acquired after Jutland
−
|
+
| probably taken from ''Lion'' or ''Princess Royal''
−
|-
 
−
| [[H.M.S. Marlborough (1912)|''Marlborough'']]<ref name=DreyerP3/><ref name=OC1916/>
 
−
| ???
 
−
|
 
−
|-
 
−
| [[H.M.S. Superb (1907)|''Superb'']]<ref name=DreyerP3/><ref name=OC1916/>
 
−
| ???
 
−
|
 
−
|-
 
−
| [[H.M.S. Temeraire (1907)|''Temeraire'']]<ref name=DreyerP3/><ref name=OC1916/>
 
−
| ???
 
−
|
 
−
|-
 
−
| [[H.M.A.S. Australia (1911)|''Australia'']]<ref name=DreyerP3/><ref name=OC1916/>
 
−
| ???
 
−
|
 
−
|-
 
−
| [[H.M.S. New Zealand (1911)|''New Zealand'']]<ref name=DreyerP3/><ref name=OC1916/>
 
−
| perhaps after [[Battle of Jutland|Jutland]]?<ref name=Brooks176/>
 
−
|  
 
−
|-
 
−
| [[H.M.S. Inflexible (1907)|''Inflexible'']]<ref name=DreyerP3/><ref name=OC1916/>
 
−
| ???
 
−
|
 
−
|-
 
−
| [[H.M.S. Invincible (1907)|''Invincible'']]<ref name=DreyerP3/>
 
−
| ???
 
−
|
 
 
|}
 
|}
 +
 +
From these two sources, it seems possible to trace the service of 5 tables.  The first three ships received tables upon completion (or soon thereafter), and retained them through the war, but ''Lion'' and ''Princess Royal'' sent their original tables to the 2 training establishments sometime ''after Jutland'' but before mid 1918 when they are listed in the Dreyer Handbook as having Mark IV* tables, which must have been new units owing to the availability of 2 for the shore facilities.
  
 
==See Also==
 
==See Also==

Revision as of 17:07, 26 August 2009

Mark III Dreyer Table c1912
Table now has a single deflection drum but lacks the second deflection drum added around February 1913.

The Mark III Dreyer Table was a refined version of the Original Dreyer Table and was the first Dreyer Fire Control Table provided for naval service, first deployed in 1912 in Monarch.[1]

Mark III Dreyer Table c1918, front
This illustrates the Standard Bearing Plot and its Deflection Totaliser which were featured so prominently in the 1918 Handbook, but which may never have been widely deployed if at all.

Development

Mark III Dreyer Table Schematic c1912
Table seems to lack any deflection drum at all, which was one of its primary improvements from the Original Table.
Mark III Dreyer Table design drawing from March, 1912.
This early drawing focuses only on the general layout, but it is clear from the overall context that the early thinking was correct to the extent that it was never revisited, and the headboard is even in place, illustrating the early focus on helm-free design from the gyro-compass and relay that are already outlined there. The early bearing plot runs the depth of the table, and the bearing clock is also clearly indicated by the handle on the dumaresq.
Mark III Dreyer Table design drawing from June, 1912
This drawing illustrates detailed thinking on positioning the components on the table and integrating their function as required. The design of the dumaresq and its underslung bearing clock may have been completed, as its handle is now angled as it would remain in subsequent drawings.
Mark III Dreyer Table as could have appeared c1918, back
Another view of the same configuration rendered above shows a Wind Dumaresq on the right would have occupied the area freed up by use of the smaller bearing plot.
Mark III Dreyer Table operators, c1918
This is also based on the configuration outlined in the 1918 Handbook but perhaps not really adopted in service.

Five of what was to become known by March 1914 as the Mark III tables were ordered in February 1912 even as the design was being finalised. It generally resembled the capabilities of the original Dreyer table, but by March 1912, it boasted these improvements:

  • the paper plots were now driven by electric motors (with a fallback to hand crank)
  • the components reorganized to place the bearing plot on the left, dumaresq in centre and range plot on right
  • dumaresq now had a means to have a gyro-compass relay update own ship's heading
  • a backboard was fitted to display a gyro-compass receiver and Forbes Log.
  • a cylindrical deflection drum was added to the bearing plot to relate bearing rate to Dumaresq Deflection.

By February 1913, the design had further matured to "probably include" the following:[2]

  • A bearing clock was added to help keep dumaresq updated for enemy bearing.[3]
  • A second deflection drum was to be added to the bearing plot to relate bearing rate to Gun Deflection.
  • Automatic transmission of ranges to the guns. The design drawing for what would later be called
  • The differential gear (later known as the spotting corrector) considered optional in previous drawings was to be issued with all further tables.
  • A means of transferring rates from dumaresq to range clock.[4]
  • A means of factoring in own ship's lateral slip through the water as it turns, but this did not work out readily and was deferred in July 1914, and allowed to fall into obscurity.[5]Slip was handled inelegantly even in postwar use of late model Dreyer tables.[Citation needed]
  • Plans to relay enemy heading and range rate to the control position (possibly this was considerably delayed, later to be manifested as ''The Repeater'' outlined in the 1918 Handbook.
  • A Time-of-Flight corrector for gun range was mentioned, but this correction continued to be calculated by the separate Dreyer Calculator and entered via the spotting corrector differential throughout the war and into the 1930s.[6]
  • Equipment to permit the plotting of ranges from multiple rangefinders. This did not happen promptly. See the discussion on the general evolution of Dreyer range plots.
Overall Dimensions (1918)[7]
Width 9 feet, 1.5 inches
Depth 4 feet, 2 inches
Height of Range Rate Grid 3 feet, 5 inches
Height of top of dumaresq 5 feet, 9 inches

Motive Power

Power for drawing paper through the plots and the range and bearing clocks was provided by an electric motor with a speed governor. Should power fail, an alternate hand-drive placed behind the table could be used. The person working this handle observed a stop-watch in a box behind an etched glass cover which revolved as he worked his handle. By keeping the etching in line with the stopwatch's hand, the correct speed to regulate the table's activity was delivered.

The Mark III's power source established a design pattern followed closely by later models except the Mark I and Mark I* which relied solely on hand crank power.

Dumaresq

An adapted Dumaresq Mark VI with fixed and simplified dial plate was fitted, with a means of permitting the gyro-compass to maintain own heading. A bearing clock and range clock were housed underneath it.

Range Clock

The range clock was underneath the dumaresq and the handle for setting its range rate also moved an indicator in a slot along the line of bearing in the dumaresq's fixed dial plate. In this arrangement, when the operator kept this indicator in line with the dumaresq's enemy bar indicator, he was maintaining a consistent range rate for the hypothesis established by the present dumaresq configuration.

The range clock's output shaft fed a differential which drove the carrier for the red clock range pencil across the range plot and permitted a tuning handle to quickly position the pencil to the desired range.

Bearing Clock

A bearing clock with a disc-and-roller variable speed drive similar to that of the range clock also sat under the dumaresq. Despite its fairly late appearance in design specifications, the handle for setting a bearing rate is clearly visible in drawings dating back to June 1912[8] and is perhaps illustrated in drawings dating from March 1912.[9]

The clock could be set to any rate between +/- 15 degrees per minute by a handle with an indicator scale jutting out from the base of the dumaresq housing.[10]

Spotting Corrector

[TO BE CONTINUED - TONE] this largely is correct for Mark I table but not Mark III

The spotting corrector in the 1918 handbook features:

  • Output worm shaft for the plot range pencil holder
  • Spotting handle to enter corrections
  • Straddle correction hand (for applying corrections from a Dreyer Calculator)
  • A digital Gun range counter (on the table)
  • Commutator to relay gun range to control positions and conning tower
  • A flexible shaft to carry gun range to the deflection drums of the standard bearing plot

A hand-worked pedalling clutch located near the tuning handle allowed the plotted range to be tuned without altering the gun range.

Range Plot

The Mark III's range plot set the pattern for those on the later tables Mark IV, IV*, V and probably II; a large surface placed on the right, with a range rate grid positioned over it.

Rate Grid The rate grid grew in sophistication by war's end, from one that had irregular markings to translate its wire angles to range rates to one with linear range rate markings, a flexible shaft to keep it aligned to the rate on the range clock, and a means of temporarily deflecting it to explore rates at variance with that set on the clock.

Plotting Range Cuts Like most of the tables, the Mark III tables' means of plotting range cuts evolved over time:

  • Initially, a single Argo RF's ranges were plotted in a fully automatic manner. This mechanism could be disconnected in favor of manual penmanship should it fail or should the results of more (or simply other) RFs want to be plotted.
  • Ambitions for replacing this with a means of plotting cuts from multiple RFs were probably alluding to the failed Macnamara's Plotter.
  • Manual Brownrigg Keyboards were used on many Dreyer tables by Jutland, but it is unclear which Mark III tables might have had this in place of their initial automated plotting mechanism.
  • Manual Range Typewriters were deployed widely in 1917.[11]

Range Pencils Initial production tables had a single red pencil to plot clock range. As early drawings imply it was first installed, it appears that the tuning handle had no pedalling clutch and so intrinsically altered clock range and gun range when it was used. This implies that the tuning handle would only be used at the beginning of an encounter.

Plotting Ranges 2,000 - 16,400 yards
(a +8,000 yard extended scale added later allowed plotting to 24,400 yards)[12]
Paper width 36 inches
Scale 400 yards/inch
Paper speed 2 inches / minute

The extended range scales were likely fitted to tables as opportunity around around the time (1915?) such a modification was made to ???? (Brooks)[Citation needed].

Bearing Plot

On plans drawn up in 1912-1913 and outlined in a Technical History drafted by Dreyer, the bearing plot was on paper 15 inches wide with a simple rate grid whose irregular edge markings as it was rotated converted the angle of rotation into a number of degrees per minute of bearing rate. By February, 1913, a single deflection drum could convert the bearing rate of the grid's inclination to a gun deflection.[13]

The Handbook for Capt F.C. Dreyer's Fire Control Tables, 1918 indicates that these were at some point to be provided with standard bearing plots[14], but these units received such scant service before the introduction of G.D.T. gear that it is hard to bank that many were actually fitted.

Deployment

The Dreyer Handbook of 1918 lists some ships with Mark III tables, with those no longer in active service crossed out by hand at some later date, and those lost before promulgation not listed at all. Those appearing in that document are footnoted below[15].

In 1913, Dreyer listed the ships he claimed actually received the first 5 Mark III tables delivered.[16]

Ship using Mark III table Date equipped Notes
King George V[16][15] 1913 or earlier through mid 1918 or beyond retained to end of service[17]
Thunderer[16][15] 1913 or earlier through mid 1918 or beyond retained to end of service[Inference]
Monarch[16][15] 1913 or earlier through mid 1918 or beyond retained to end of service[Inference]
Lion[16] 1913 or earlier through Jutland at least[Citation needed] replaced at some point with Mark IV* table
Princess Royal[16] 1913 or earlier through Jutland at least[Citation needed] replaced at some point with Mark IV* table
Excellent[15] acquired after Jutland probably taken from Lion or Princess Royal
Chatham Gunnery School[15] acquired after Jutland probably taken from Lion or Princess Royal

From these two sources, it seems possible to trace the service of 5 tables. The first three ships received tables upon completion (or soon thereafter), and retained them through the war, but Lion and Princess Royal sent their original tables to the 2 training establishments sometime after Jutland but before mid 1918 when they are listed in the Dreyer Handbook as having Mark IV* tables, which must have been new units owing to the availability of 2 for the shore facilities.

See Also

Footnotes

  1. ↑ Brooks. Dreadnought Gunnery and the Battle of Jutland. p. 159.
  2. ↑ Dreyer & Usborne. Technical History, pp.47-8.
  3. ↑ this is somewhat ambiguously stated
  4. ↑ This was not to materialise until the advent of the Electrical Dumaresq
  5. ↑ Brooks. p. 169.
  6. ↑ Brooks. p. 169, footnote 141.
  7. ↑ Dreyer Handbook, 1918 p. 90.
  8. ↑ Technical History, Fig. 7.
  9. ↑ Technical History, Fig. 4.
  10. ↑ Technical History, Figs. 3, 7.
  11. ↑ Brooks. Dreadnought Gunnery, p. 173.
  12. ↑ Dreyer Handbook, 1918 p. 17.
  13. ↑ , pPollen Aim Corrector System, Part I. Technical History and Technical Comparison with Commander F. C. Dreyer's Fire Control System, pp. 47-8.
  14. ↑ Handbook for Capt F.C. Dreyer's Fire Control Tables, 1918. pp. 13-15.
  15. ↑ 15.0 15.1 15.2 15.3 15.4 15.5 Handbook of Captain F.C. Dreyer's Fire Control Tables, 1918. p. 3.
  16. ↑ 16.0 16.1 16.2 16.3 16.4 16.5 Dreyer & Usborne. Technical History. pp. 11-2.
  17. ↑ not listed as having another, and decommissioned soon after that source's publication

Bibliography

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